Ah, right. We didn't go this route for text help, the only time we did this was for some dodgy web submission software for the finance team. It might be that you can't actually do this with the certificate texthelp supply.
Second, when I add a 'code signing' and then I can add a certificate to the list, I cannot find the 'Text Help Systems' certifiacte in the list. I try to add one by file since I have exported the certificate, but it tells me only 'self-signing' certificates can be added. At this point I am stuck.
If you do it as a domain policy, it will be picked up by any computers(for computer configuration) or users(for user configuration) in the OU you apply it to.
One last question, if I were able to set this up as you have described, does it feed back to the rest of the network, or is this just for that PC?